Magnetic arc starter for welding machines



.May 7, 1946. J. M TYRNER MAGNETIC ARC STARTER FOR WELD ING MACHINES Filed April 21, 1945 liwl NR 5 m ML m M j Patented May 7,

UNITED stares PAT Eur GFFlCE MAGNETIC 'ABG STABTERTOR WELDING MACHINES Joseph Tanner,- New York, N. Ytasslrncr to ;Alr Reduction Company, Incorporated, a corporation of New York Application April 21, 1945,,Serial'No. 589,609 (01. 314-66) 4 Claim.

This invention relates to improvements in devices used in connection with automatic arc welding machines for establishing the are between the electrode and the work. v

- Automatic welding machines for carrying out various welding operations are. commonl provided with a support for holding the electrode and for progressively moving the electrode downwardly toward the work underthe control-of voltage-responsive mechanism or other types of control devices which feed the electrode support or holder toward the work as the electrode is con sumed. Devices have also been provided in connection with the support or electrode holder for establishing the are between the electrode and the work which is to be welded. I

The primary object of the present invention is v to provide an improved automatic device of siman automatic device of the type referred to which has a delayed action adapted to permit th flow of a heavy current from the electrode to the work before the electrode is drawn therefrom in-order to establish the proper welding arc. I

An improved feature of the present invention is the provision of an automatic device of the type described which includes a bracket attached to the electrode support of a welding machine, for

example, an automatic welding machine. the

- projecting'in the same .direction as that of the arms of the bracket and in'which a winding of large wire is providedaround the central pole of the magnet. According to a preferred construction, the three poles of the magnet are mounted in line with the arms of the bracket, the arms projecting slightly beyond the ends of the poles and being turned in toward each other to provide parallel bracket sections on .each side of the magnet which serve as guide means for the crossbar. In this preferred construction, the armature is preferably a long heavy bar extending across the ends of the three magnet poles, and the guide means comprises a bolt attached to each end of the cross-bar and extended through holes in the spaced horizontal sections of the bracket arms.

Means is also provided for adjusting the range vof movement of the armature with respect to the ends of the poles of themagnet thereby controlling the length of the are between the, electro'd and the work. Other features, objects and advantages of the improved device of the present invention will be bracket comprising a pair of substantially spaced arms projecting in the general direction of the support, a magnet-mounted in the bracket between the arms and spaced therefrom, the magnet including a winding of large wire, one end of which is adapted to be connected-to a source of welding current, a cross-bar having an armature member on one side extending opposite the end 'of said magnet, a movable guide means for securing the ends of the cross-bar to the respective arms of the bracket and adapted to permit limited movement of the armature toward and away from the magnet, an electrode holder secured to the underjldo of the bar, and a conductor for connecting laid winding to the electrode holder.

nnother 'feoture oi the invention is the provision of a magnet for the automatic device referred to which is provided with three pole pieces apparent to'those skilled in the art from thefollowing more detailed description thereof, taken ,in connection with the accompanying drawing forming a part of this application.

Inthe drawing A Fig. 1 is a vertical front view, partly in section, of a device for automatically establishing an arc between a welding electrode and the work to be welded, constructed in accordance with the featuresof the present invention.

Fig. 2 is an end view partly in section or the device shown in Fig. 1.

Fig. 3 is a horizontal sectional view taken on the line 3-3 of Fig. l in the direction of the arrows.

Referring to the drawing, the apparatus of the present invention comprises a supporting member l0 which may be a part of a conventional automatic or other welding machine and which may be moved downwardly by such a machine under any type of control for feeding an electrode held thereby toward the work to be welded as the electrode is consumed. The supporting member It may be mounted in vertical position or at any other angle; depending upon the design of the paratus for operating the support It, thedraw in: anddescription does not include such apparatus. It is to be understood, however, that the support I ll may be moved at a controlled rate with attached to the bottoni of the cross-bar 2|.

respect to the work to be welded, as for example along a seam, or the work may be moved while the support and the electrode held thereby is kept in a fixed location, except for the slow axial movement toward the work as the electrode is consumed. r

A bracket member l2 of bar stock, as indicated;

.is attached to the lower end of the support II.

The bracket includes the upper horizontal section, as indicated, and substantially spaced downwardly extending integral arms is which terminate in horizontal inwardly extending integral flanges IS. The arms I extend generally in a direction parallel to the support it while the upper and lower horizontal sections of the bracket are provided with holes inwardly of the arms I! for receiving movable guide members or bolts I8. The lower ends of the bolts is are attached, respectively, to the opposite ends of a cross-bar 20 which is mounted parallel to the flanges It, the bolts being attached in fixed relation to the bar by means of a nut and washer, as indicated. The upper endsof the bolts it are each provided with a pair of nuts 22 so that they may be locked to the bolts-l8. v

A magnet 24 is symmetrically attached to the under side of the bracket l2; th core of which comprises two integral end poles II and .an integral central pole 2|. Themagnet has approximately the width of the stock of the bracket l2, the poles being mounted in alignment with the bracket arms I4 and all projecting the same distance from. the upper part of the bracket. The projecting ends of the poles II and 22 extend between the flanges It to the position indicated in Fig. l. The cross-bar 20 carries an attached armature bar 30 which is of the same width as the poles of the magnet and is approximately the same length as the magnet is wide. The magnet 24 includes a winding 22 which comprises only a few turns of a relatively large insulated wire which is'provided with a conductor" which is connectedto a source of welding current supply,

,not shown. The opposite end of the winding 32 is provided with a conductor 38 which is electrically connected to a metal electrode holder 38, The holder 2| is drilled centrally to receive-a welding electrode 40 which is held in placefby means of a screw 42. Y

.The electricalcircult through the apparatus, as shown, includes the conductor 24 which'is connected to a transformer, welding generator or other suitable source of welding ,current, from which current flows through the turns of the winding 82, the conductor ll, holder 38, and electrode 40, to a work piece 44 which is in turn connected back to the source of current by means of a conductor 4'. To prevent the welding current from passing from the electrode holder 38 back through the support, the holder may be insulated from the cross-bar 20, or this bar may be made of insulating material, as indicated'ln Y Fig. 1,.

In the operation ofthe device of the presentinvention, a welding machine to which the device is attached is operated to lower the support ll until the projecting end of the electrode 4| comes in contact with the work 44, as shown inFlg. 1. As the welding current flows through the winding 32 and the electrode All into the [work 44, the magnet 24 is energized, and after some/time lag, the armature 30 is drawn up into contact with the poles of the magnet 24. This movement of i the armature 30 lifts the electrode 4| out of contact with the work I and draws an are between the electrode and the work. However, the armature 30 is not drawn up immediately upon the passage of the current through the winding 32 because of the time lag involved in building up a magnetic held in the magnet provided with the small number of turns, and because of the inertia of the armature and the other movable parts of the device connected therewith. This delay permits the flow of a heavy current from the electrode 4f to the work before the electrode is drawn p.

The length of the arc desired between the end of the electrode 4|! and the work 44 is determined by the clearance between armature l0 and the ends of the pole pieces 2! and 2! of the magnet. The correct distance for a particular welding operation may be obtained by adjusting the spacing between the armature l0 and the pole pieces of the magnet by means of the nuts 22 on the bolts ii.

The automatic device as described above provides a very simple automatic construction for drawing the electrode away from the work and establishing the desired arc for effecting a weld- V stantial alignment with the support I I.

When the welding current is not turned on, the weight of the bar 20, armature ill and other connected elements causes the armature to move away from the ends of the poles of the magnet, and the assembly is carried by the nuts 22 which engage the upper horizontal surface of the bracket I2. If desired, light coil springs may be included around the bolts between the flanges l8 and the bar 20, to keep the mechanism in its extended position, except when the current is turned on.

The use of a relatively long bar 29, the substantially spaced guidearms and the retaining bolts its function or operation. Such changes are coni templated as coming within the scope of the present invention, as defined by the appended claims.

What is claimed as new is: I 1. In an arc welding apparatus, a device for automatically establishing an are between a welding electrode and .the work to be welded, comprising a bracket having a pair of spaced project-- ing substantially parallel arms, a magnet mounted in the bracket between the arms in spaced relation thereto, said magnet including three spaced pole pieces projecting in the same direction as said arms, a winding of large wire around the central pole of said magnet one end of which is asaavn 3 adapted to be connected to a source or weidinl current, a cross-bar having an attached armature member extending across the ends or said pole pieces, movable guide means for securing the ends of said bar to the respective arms of the bracket, an electrode holder secured toth'e under side 01' said bar, and a conductor connecting the other end of said winding to the electrode holder.

magnet one end of which is adapted to be connected to a source of welding current, a cross-bar having an attached armature member ex 8 across the end of said pole piece, a movable de member secured to each end 01 said bar, said guide members being slidably, connected to the respective arms of the bracket, an electrode holdersecured to the under side of said bar, and a lead wire connecting the other end of said winding to I the electrode holder.

3. In an arc welding apparatus, a device for automatically establishing an arc between a welding electrode and the work to be welded, comprising an electrode mounted in a holder attached to the under side of a cross-bar, an armature bar 7 attached to-the upped side of said-cros's-bar, a bracket mounting a ma ne guide means interconnectingtheendsorsaidcross-barandbraoket as and to mount said armature opposite the I pole of said magnet and in limited movable reia-' tion thereto, a support attached to said bracket and adapted to be carried by a welding apparatus, said magnet including a winding 0! large wire interconnected between a welding current source and the electrode, whereby said electrode is drawn up by the magnetaft'er the welding current is turned on.

l0 4. In an arc welding apparatus in which a weldingelectrode is contacted with the workto be welded and then supported adjacent the work during the welding operation, a device for automatically drawing the electrode away from the 5 work and for establishing an are between the electrode and the work, comprising an electrode holder attached to the under side 0! a cross-bar. an armature attached to the upper side of said cross-bar, guide elements attached to each end oithebarandspacediromthearmaturea bracket having side members adapted to receive said guide elements, a magnet mounted between the side elements "of said bracket opp site said armature, said magnet including a winding hava ing a relatively smallnumber 0! turns or large wire interconnected between a source or welding current and the electrode holder, said magnet and windingbeingarrangedteprovideatimel e in the build-up of the magnetic iield ai'ter the goweldingcumntisturnedcnwherebyaheavy current flows-directly from the electrode tothe work when the elsctrodeis initially in contact therewith. 

